Dispensing container



Dec. 27, 1949 a. BANNISTER 2,492,330

DISPENSING CONTAINER Filed Oct. 25, 1945 Patented Dec. 27, 1949 UNITED STATES PATENT OFFICE DISPENSING CONTAINER Bryant Bannister, Pittsburgh, Pa., assignor to James Howard Young, Pittsburgh, Application October V23, 1945, Serial No. 23,905! Claims. (01. 65-57) This invention relates to a dispensing container and more particularly to a salt shaker. In general, the object of the invention is to provide a novel and improved .dispensing container for holding a hygroscopic commodity such as salt and for maintaining and conditionin the atmosphere within the container so that the commodity may be dispensed in a freely flowing condition for relatively long periods of time, particularly when the container is used under atmospheric conditions of high humidity.

A further and more specific object of the invention is to provide a novel salt shaker which is capable of freely dispensing salt in an eflicient manner over long periods of time without attention, particularly when the shaker is subjected to atmospheric conditions of high humidity.

A still further object of the invention is to provide a novel dispensing container for holding .a hygroscopic commodity such as salt embodying a novel desiccant which can be readily revived after having become saturated.

A still further object of the invention i to provide a novel dispensing container for the purpose specified, embodying a desiccant capable of visu ally indicating its approach to a saturated condition.

With these general objects in view, the invention consists in the dispensing container, and particularly in the salt shaker hereinafter described, and particularly defined in the end of this specification. v

In the drawing, Fig. 1 is a vertical sectional view of one form of .salt. shaker embodying the invention; Fig. 2 is a side elevation of the same; Fig. 3 is a section on the line 3-3 of Fig. 1; Fig. 4 is a bottom plan view of the shaker shown in Fig. .2; Figs. 5 and 6 are views in vertical sections and side elevations respectively of a modified form of shaker embodying the invention.

In general the invention contemplates a dispensing container for salt and other hygroscopic commodities in which the commodity is maintained in the container in a freely flowing condition for relatively long periods of time even when the container is used under atmospheric conditions of high humidity. As far as I am aware, a salt shaker capable of this accomplishment is not commercially available. I

It is recognized that heretofore attempts have been made to solve this problem, and that these attempts may be resolved into two general classes of dispensing containers. One classmay be described as a container provided with a continuously open dispensing orifice in the top thereof and having a desiccant designed to absorb moisture from the commodity and from the air within the container in contact therewith. In practice, this class of dispensing container has proven to have little utility because of the fact that as the desiccant withdraws moisture from the air within the containner, a continuous flow of moisture occurs from the outside atmosphere into the body of air from which the moisture is thus being drawn by the desiccant, and as a result action of the desiccant is exerted upon the inexhaustible supply of humidity in the air outside of the container, the action being similar in effect to-attempting to dry by the use of a limited quantity of a desiccant an extremely large body of hum-id air. It will, therefore, be seen that in this-type of container the desiccant soon becomes exhausted and the salt or other commodity within the container rapidly becomes moist and nonfreeiy flowing. The other attempt to solve the problem has been to provide a dispensing orifice of a container with an automatic valve for closing the orifice except when the salt was being dispensed. While this had a slight efiect in extending the utility of the dispensing container, experience has demonstrated that the influx'of humidity during the periods of dispensing was sufficient to enable the impurities in the salt to absorb enough moisture to wet the particles of the salt producing a sog y condition and clogging the dispensing orifice, or orifices.

The present invention contemplates a dispensing container for salt and other hygroscopic commodities wherein the body of air within the container is maintained during normal use of the dispensing container over relatively long periods of time in a substantially dehydrated or at least dehydrated below the critical point above which the salt or other commodity will become moist and non-freely flowing. This result is accomplished by the cooperative action, as will be described, on the body of air within the container of a desiccant and an automatic dispensing valve operative to cut off the body of air in the com tainer from the humid air outside the container during the non-dispensing periods of use of the container. The valve is constructed to minimze the amount of humidity which may infiltrate through the valve into the container during dispensing periods and the desiccantis designed to be capable oi not only dehydrating the body. of air within the container but also of maintaining the moisture content thereof over relatively long periods of time below the critical point above 3 which the salt or other commodity becomes moist and non-freely flowing.

Considerable research and experiments have been performed in order to study the various factors which enter into the solution of the problem of providing a satisfactory salt shaker which would maintain salt in a freely flowing condition when used even under excessively humid conditions. It has been recognized that the deliquescence of common table salt is due to the presence of small amounts of impurities, magnesium chloride being the worst offender. The magnesium chloride absorbs moisture from the atmosphere, and as a result the surfaces of the salt crystals become moist and dissolve in the moisture to give concentrated solutions. Since these solutions have vapor pressures lower than the partial pressure of the water vapor in the air,

more moisture is absorbed and the process continues until the vapor pressure of the solution is equal to the aqueous pressure in the air.

The deliquescence point, that is the minimum water vapor concentration in the air required to cause deliquescence was determined experimentally. Temperatures of 65 F. and 95 F. were taken to be the average lower limit of room temperature and the aver-age upper limit of room temperature respectively, and it was determined that the deliquescence point for ordinary table salt expressed as inches of mercury at the respective temperatures was between the limits of 0.4 and 1.4. Silica gel was selected as the most satisfactory desiccant and is preferably pre-treated with cobalt chloride as a moisture indicating agent. It was determined experimentally that the silica gel would protect table salt from deliquescence until the silica gel has adsorbed about 31.5% water. After this concentration had been reached, further exposure of the table salt to high humidity resulted in rapid deterioration of the condition of the salt rendering it non-freely flowing. It was further discovered that the color change from blue to pink of the cobalt-chloridetreated silica gel did not occur until a point was reached in the adsorption of water, at which the silica gel ceases to protect the table salt, or in other words, after the silica gel had adsorbed about 81.5% water. The silica gel lends itself particularly to revivification in a practical and economical manner. It was found, for example, that after the silica gel had adsorbed at least 31.5% of water, that it could be rapidly dehydrated at 300 F. the percentage of water remaining being as follows:

Per cent 20 minutes 13.0 35 minutes 3.8 60 minutes 0.4 120 minutes 0.0

During the research and experimental work above referred to, it was determined that ordinary table salt when exposed to 100 relative humidity at a room temperature of F. after about three hours had become too moist for satisfactory use in a shaker and it was found that the salt had gained in moisture content only 1% by weight. In other words it is only necessary for the salt to absorb 1% of its weight of moisture, to render it incapable of being shaken from a salt shaker.

I have discovered that by utilizing a desiccant of silica gel, or any known equivalent, in an amount approximating one-fifth of the volume of thesalt shaker and by providing the salt shaker with an automatically operating dispensing valve,

4 that the body of air within the shaker and in contact with the salt may be effectively maintained over relatively long periods of time below the deliquescence points of from 0.4 to 1.4 inches of mercury whereby the salt is maintained in a freely flowing condition.

I have conducted experiments which prove that the cooperative action of the valve and desiccant upon the body of air within the container, when used in accordance with my invention, provides an efiect which is not realizable by the use either of the valve or of the desiccant alone, and which is far greater than the sum of the two acting separately where the said cooperative action does not occur. These experiments have shown that silica gel, the preferred desiccant for the purpose, when used in an open dispenser in an amount equal to about one-fifth the volume of the dispenser, protects table salt from becoming too moist to pour freely for a period of only three days, or less, under such conditions of high humidity as occur commonly near the sea shore. Since it is not common practice tofill containers every three days, the use of a desiccant in a container with an open orifice is not a satisfactory solution of the problem.

I have found, too, that when ten grams of salt is protected by five grams of silica gel, at very high humidities, the salt ceases to pour freely after it has absorbed about one-tenth of a gram of water, whereas the silica gel, at the same time, has taken up about one and one-half grams of water or fifteen times as much as the salt. These figures readily explain the marked improvement realized in my invention by using a desiccant in conjunction with the valve. The valve unavoidably admits some moist air to the container during shaking and by infiltration. Without the desiccant, using the quantities mentioned above, the salt becomes moist and non-freely flowing after the valve has allowed passage of approximately one-tenth of a gram of water, whereas, with the cooperative action of the desiccant, this condition appears only after the valve has permitted passage of sixteen times this quantity of water.

The outstanding advantage of my invention and the characteristic which distinguishes it from previously known dispensers, is the interaction between the valve and the desiccant whereby the valve is not required to protect the salt directly, but accomplishes this purpose by maintaining the desiccant, over long periods of time, in such condition that it is able to condition the entering air to a moisture content which is below the critical point above which the salt or other commodity will become moist.

Referring now to the drawings which illustrate the invention as embodied in a salt shaker for household use, in the embodiment shown in Fig. 1, l 0 represents the body portion of the container which may be made of any corrosive-resisting material but which is preferably of glass and of asize designed to hold any usual or preferred amount of salt. The body portion I0 is provided with a hollow cap portion or closure member l2 having a dispensing orifice Hiin the upper end thereof. As shown, the orifice M comprises a small cylindrical passage formed by a cylindrical portion l5 depending from the under-surface of the top of the cap, and for the usual sizes of salt shakers it is preferred that the orifice should be about it" in diameter with the upper edge thereofground or otherwise forming an accurate seat for;

erably provided with at downwardly extended portion 18 arranged to extend through the cylindrical passage I4 and for a short distance beyond the lower end thereof being of such size and shape as to provide sufiicient clearance for the free passage of the saltduring the shaking operation. The lower ends l9 of the extended portion l8 are preferably flared to prevent the valve from becoming detached from the cap I2 while permitting the valve to open suificiently when the salt shaker is inverted during the usual shaking of dispensing operation. The valve is preferably gravity-operated so that as long as the shaker occupies a vertical position when not in use, the valve effectively closes the container and cuts 01f the air within the container from the outside air.

The lower end 2| of the cap I6 is tapered and arranged to be snugly fitted into the upper end of the body ID, a suitable gasket 23 being preferably provided so that an air-tight joint is maintained at this point permitting the cap to be removably mounted on the container. The cap I2 is preferably made of a high-temperature glass for purposes to be described.

Provision is made for operatively supporting a substantial amount of a desiccant within the cap so that when the cap is removed, the desiccant may be removed as a unit therewith, and as herein shown the desiccant, preferably silica gel in granular form, is retained within the hollow cap by a perforate tube 25 arranged to frictionally engage and fit over the cylindrical downwardly extended portion 15 of the cap above referred to, and the bottom of the tube 25 is flared outwardly into engagementwith the interior surfaceof the lower portion of the cap as shown, thus providing an annular chamber for retaining the desiccant in a position to expose the desiccant to the air within the salt shaker.

With this construction, it will be observed that the container is substantially air-tight at all times except during the dispensing operation, and that both the desiccant and the valve cooperate to condition the body of air within the container in order to maintain its moisture content below the amount that renders the salt non-freely flowing. In operation, as the salt is dispensed, the small amount of moist air which may be infiltrated into the body of the container during the short period that the valve is open is conditioned and dehydrated by the desiccant with the result that a salt shaker embodying the present invention maintains the salt in a freely flowing condition for relatively long periods of time under normal conditions of use, and even when the shaker is subiected to conditions of use in an atmosphere of high humidity the salt is maintained in a satisfactory freely flowing condition for periods well over a month whereas any salt shaker of the prior art of which I am aware, would become clogged and salt rendered non-freely flowing under comparable conditions of humidity within a day or two.

r In Figs. and 6, I have illustrated a modified form of salt shaker embodying the invention in which the body portion 30 of the shaker has the upper end 32 thereof formed integrally with the body portion and is provided with a dispensing opening 34 having a conical valve 35 and valve seat 38 constructed as above described in connection with the embodiment of Fig. 1, The lower portion of the body is open and. threaded for the reception ofa closure 40 .for enclosing the bottom of the shaker. A gasket 4| is disposed between the body and closure 40 to formanair-tight seal; Inpractice, it is preferred to construct the body portion of, glass and to mold the same with a tapered interior as illustrated for convenience of manufacture and in order to permit the disposition of a desiccant container or cartridge 42 in the lower portion of the body portion as shown. The desiccant container 42 may be formed of corrosion-resisting material, preferably of glass, and having its upper surface perforate for exposing the salt and air withinthe shaker to the dehydrating effect of the desiccant.

It will be observed that the construction of the shaker illustrated in Fig. 1 has the advantage that the desiccant is enclosed within a glass cap and is exposed to view so that the condition of the silica gel can .be observed toshow when it needs revivification. As the form of silica gel which I use approaches'saturation, it changes in color from a deep blue topink and thereupon by constructing the cap of high-temperature glass the entire cap unit containing the desiccant may be placed in the oven and exposed to a temperature approximately300 F. for between 20 to 30 minutes to substantially complete revivifying the'desiccant. 'Theconstruction of the'shaker disclosed in Figs. 5 and 6 lends itself to simplicity of manufacture, and the desiccant itself may be contained within the container 42 as shown forming in effect a capsule which may be placed in the oven and exposed to heat as above described to revivify it.

From the description thus far it will be observed that the present construction of salt shaker will maintain thesalt in a freely flowing condition for relatively long periods of time, as for example from one to two months, under conditions of humidity which would render any prior types of salt shakers inoperative for all practical purposes after a 'few days.

While it is preferred to use cobalt-chloride treated silica gel as the desiccant, other materials such as activated alumina, ferric hydroxide and sodium sulphate may be usedif found advantagenus. Havingthus described the invention, what is claimed is:

1. As a new article of manufacture, a salt shaker particularly adapted to maintain ordinary table salt in a dry, freely flowable conditionand capable of converting salt too moist forready dispensing, into salt dry enough to'be capable of flowing freely, said shaker comprising: a moisture impervious transparent container including a body portion open at one end thereof and a closiu e portion closing the open end of said body portion; an air-tight sealing gasket between said closure portion and body portion for prevent ing air containing moisture from entering said container; an automatic, gravity-seating, dispensing valve carried by one of said container portions operative in open position to dispense salt from said container and to admit air into said container, and to out ofi communicationbetween the air within said container and the air outside said container so long as said container is in a substantially upright position, said container portion carrying said dispensing valve having a seat for said dispensing valve providing a "substantial line contact with said dispensing valve; and a heat revivifiable body of desiccant within said container visible through :at least one or said container portion-s; an element retaining said body of desiccant in a-confinedmass within said'contamer, said element and mass being sep arable tram-said body portion to permit heat; re-' vivification of said desiccant, said desiccant being in suflicient amount and of suflicient power so that in competition with the desiccant effect of the'magnesium chloride in the salt, it is capable of effecting the aforesaid conversion and to dry and maintain the salt in a substantially dry, freely fiowable condition for a period of time greatly in excess of that required to dispense at least one filling of the container in normal use, notwithstanding the repeated admission of small volumes of moist air into said container by said dispensing valve at times when said container is in use and said valve is open.

2. As a new article of manufacture, a salt shaker particularly adapted to maintain ordinary table salt in a dry, freely fiowable condition and capable of converting salt too moist for ready dispensing, into salt dry enough to be capable of flowing freely, said shaker, comprising: a moisture impervious transparent container including a body portion open at one end thereof and a closure portion closing the open end of said body portion; an air-tight sealing gasket between said closure portion and body portion for preventing moisture from entering said container; an automatic, gravity-seating, dispensing valve carried by said closure portion operative in open position to dispense salt from said container and to admit air into said container, and to cut off communication between the air within said container and the air outside said container so long as said container is in a substantially upright position, said closure portion having a seat for said dispensing valve providing a substantial line contact with said dispensing valve; a heat revivifiable body of silica gel within said container visible through one of said portions of said container and capable of color change when substantially saturated with moisture, said desiccant having a volume equal to about the volume of the container and of sufficient power so that in competition with the desiccant elfect of the magnesium chloride in the salt, it is capable of effecting the aforesaid conversion and to dry and maintain the salt in a substantially dry, freely fiowable condition for a period of time greatly in excess of that required to dispense at least one filling of the container in normal use, notwithstanding the repeated admission of small volumes of moist air into said container by said dispensing valve at times when said container is in use and said valve is open an element retaining said body of silica gel in a confined mass within said container, said element and mass being separable from said body portion to permit heat revivification of said desiccant.

3. As a new article of manufacture, a salt shaker device particularly adapted to maintain ordinary table salt in a dry, freely fiowable condition and capable of converting salt too moist for ready dispensing, into salt dry enough to be capable of flowing freely, said shaker comprising: a moisture impervious container comprising a body portion open at one end thereof and a transparent glass closure portion closing the open end of said body portion; an air-tight sealing gasket between said closure portion and body portion for preventing moisture from entering said container, said closure portion having a dispensing orifice; an automatic, gravity-seating, dispensing valve mounted in said orifice and being operative in open position to dispense. salt from said container and to admit air into said container and to cut off communication between 8 the air within said container and the air outside said' container so long as said container is in a substantially upright position; a perforate tube in said closure portion having its upper end surrounding said orifice and valve, and having its lower end flared outwardly toward said closure portion, thus providing an annular chamber in said closure portion; and a heat revivifiable desiccant in said annular chamber visible through said glass and capable of color change when substantially saturated with moisture, said desiccant being in suflicient amount and of sufficient power so that in competition with the desiccant effect of the magnesium chloride in the salt, it is capable of effecting the aforesaid conversion and to dry and maintain the salt in a substantially dry, freely fiowable condition for a period of time greatly in excess of that required to dispense at least one filling of the container in normal use, notwithstanding the repeated admission of small volumes of moist air into said container by said dispensing valve at times when said container is in use and said valve is open.

4. As a new article of manufacture, a salt shaker device particularly adapted to maintain ordinary table salt in a dry, freely fiowable condition and capable of converting salt too moist for ready dispensing, into salt dry enough to be capable of flowing freely, said shaker comprising: a moisture impervious transparent container including a body portion open at one end thereof and a closure portion closing the open end of said body portion; an air-tight sealing gasket between said closure portion and body portion for preventing moisture from entering said container; an automatic, gravity-seating, dispensing valve carried by one of said container portions operative in open position to dispense salt from said container and to admit air into said container, and to out off communication between the air within said container and the air outside said container so long as said container is in a substantially upright position; and a removable cartridge in said container retained in position by one of said container portions and comprising a perforate transparent glass wall, said cartridge containing a heat revivifiable desiccant visible through said glass wall and capable of color change when substantially saturated with moisture, said desiccant being in sufficient amount and of suflicient power so that in competition with the desiccant effect of the magnesium chloride in the salt, it is capable of effecting the aforesaid conversion and to dry and maintain the salt in a substantially dry, freely fiowable condition for a period of time greatly in excess of that required to dispense at least one filling of the container in normal use, notwithstanding the repeated admission of small volumes of moist air into said container by said dispensing valve at times when said container is in use and said valve is open.

5. As a new article of manufacture, a salt shaker device particularly adapted to maintain ordinary table salt in a dry, freely fiowable condition and capable of converting salt too moist for ready dispensing, into salt dry enough to be capable of flowing freely, said shaker comprising: a moisture impervious transparent container including a body portion open at one end thereof and a closure portion closing the open end of said body portion, an air-tight sealing gasket between said closure portion and body portion for preventing moisture from entering said container; an automatic, gravity-seating,

dispensing valve carried by one of said container portions operative in open position to dispense salt from said container and to admit air into said container, and to cut ofi communication between the air within said container and the air outside said container so long as said container is in a substantially upright position; and a removable cartridge in said container retained in position by one of said container portions and having a transparent wall rendering contents of said cartridge visible, said cartridge being constructed and arranged to permit moist air to pass into the cartridge from the interior of said container, said cartridge containing a heat revivifiable desiccant visible through said transparent wall and capable of color change when substantially saturated with moisture, said desiccant being in sufiicient amount and of sufiicient power so that in competition with the desiccant efiect of the magnesium chloride in the salt, it is capable of effecting the aforesaid conversion and to dry and maintain the salt in a substantially dry, freely fiowable condition for a period of time greatly in excess of that required to dispense at least one filling of the container in normal use, notwithstanding the repeated admission of small volumes of moist air into said container by said dispensing valve at times when said container is in use and said valve is open.

BRYANT BANNISTER.

10 REFERENCES CITED The following references are of record in the file of this patent:

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